Extreme broadband multichannel ECE radiometer with "zoom" device

A new radiometer has been built up for the W7-AS stellarator which consists of a frontend with an extreme broadband mixer, two intermediate frequency (IF) parts with 16 channels each and a novel additional 16 filter section w ith variable IF. The system was designed with the future W7-X in mind. All settings can therefore be remotely changed. This "W7-X" system is integrate d into the electron cyclotron emission (ECE) systems at W7-AS. EC radiation is collected using elliptical mirrors in Gaussian optics. W7-AS results wi ll be shown. The "zoom" device is installed at DIII-D at the moment; first results are also shown. (C) 2001 American Institute of Physics.